Tokkai Hei-11-125313 published by the Japan Patent Office in 1999 discloses a metal V-belt for a continuously variable transmission. The belt elements of the metal belt of this prior art comprise a plurality of threads and grooves in a flank which is a section at which the belt element makes contact with the pulley disk. This arrangement improves the discharge characteristics of lubrication oil provided between the belt elements and a pulley disk.
In the prior art, when the height (h) of the threads is reduced by long-term use to between 30-70% of an initial height, the effective area of contact between the pulley disk and the flank corresponds to 40 to 60% of the area of the flank. It is preferred that the plurality of threads provided in the flank has a sinusoidal profile (in the shape of a sine curve). During an initial period of use of the belt elements, the effective contact surface area is low and initial wear on the threads progresses rapidly and easily. In this manner, a state of quasi-equilibrium is reached in a relative rapid manner in which the effective contact surface area is of the order of 50%.